"We are having talks with countries around the world about the implications of the legislation with regard to our expectation that countries will increasingly wean themselves of dependence on Iranian oil," she said.

"But I'm not going to give you a blow by blow of how these conversations are going with the individual countries, except that I think it's fair to say that in all of these conversations, we share an objective, which is to increase the pressure on Iran," Nuland said.

Asked to comment on former Under Secretary of State for Political Affairs Nick Burns' that India, the decisions to continue purchasing oil from Iran is a slap in the face of US, the spokesperson said the former diplomat "speaks for himself at this stage."

"He is a private citizen, so he expresses - he speaks for himself at this stage," she said. "Our goal is to continue to work with India to encourage it to do what it can to reduce its dependence on Iranian crude. And we will continue those discussions."

Asked if the US had any update on a recent bomb blast in Delhi and if it had any connection with Iran, Nuland said: "No. I don't have anything further. As I understand it, the Indians' own investigation continues."

In an op-ed in the Diplomat, a leading current affairs magazine, Burns had questioned India's ability lead over New Delhi's decision to continue to buy Iranian oil and called it a slap in the face of the United States.

"India's decision to walk out of step with the international community on Iran isn't just a slap in the face for the US - it raises questions about its ability to lead," he wrote.